to simplyfy cpu hotplug we didnt zap low mem address since we would requirethem post boot to bringup a new cpu. This caused bad effects when Suresh was testing some new code. More below.

Andrew: Please consider for -mm

-- Cheers,Ashok Raj- Open Source Technology Center

We need to dynamically map and unmap the low address mappings on demand.Originally we left these low address mappings since they were required for cpuhotplug. Due to the following sigthting, we are now doing this dynamically on demand just before we bringup a cpu and then zap when the secondary boot is complete. We defer the zap during first boot until smpboot process is complete.